Clock drawing test: Correlation with linear measurements of CT studies in demented patients

Objectives. To investigate a presumed correlation between clock drawing rat ings and linear measurements of computerized tomography (CT) studies in dem ented patients. Design. Blinded evaluations of clock drawing tests and CT studies of elderl y dementia patients were conducted by a geriatric psychiatrist and a neuror adiologist. Subjects. Fifty-one community-dwelling elderly subjects meeting the criteri a for DSM-IV diagnosis of dementia (Alzheimer's type dementia: N=31, vascul ar dementia: N=15, 'mixed' type dementia: N=5). Materials. Mini-Mental State Examination (MMSE), Cambridge Cognitive Examin ation (CAMCOG), Clinical Dementia Rating (CDR). CAMCOG derived scored clock drawings were evaluated using adaptations of Shulman et al.'s and Freedman rt Ill.'s methods. CT studies were evaluated using six different linear me asurements of brain atrophy described in the literature. Results. Of the CT linear measurements, only the Cerebro-Ventricular Index- 2 (CVI-2; bicaudate index) significantly correlated with clock drawing rati ngs (CAMCOG's clock r=-0.407, p=0.003; Shulman's method r=0.357. p=0.01, Fr eedman's method r=-0.413. p=0.003) in the dementia group. There was no sign ificant correlation between CVI-2 with demographic (age), cognitive (MMSE, CAMCOG) and clinical (duration of illness, CDR) ratings. Alzheimer's patien ts generally maintained a significant correlation between CVI-2 and clock d rawings, but vascular dementia patients did not: CVI-2 also correlated sign ificantly with the Praxis subtest of the CAMCOG in dementia and Alzheimer's patients but not in the vascular dementia group. Similarly, multiple stepw ise regression analysis showed that only CVI-2 but not the other radiologic al measures studied, was selected as the significant variable to correlated with clock drawing test ratings in the dementia group and Alzheimer's pati ents. Partial correlation analysis controlling for demographic and clinical variables shows that controlled variables had no significant effect on the relationship between clock drawing ratings and CVI-2. Conclusion. A single and easy to perform measure of caudate atrophy correla tes specifically and consistently with impairments revealed in the clock dr awing test and with a Praxis subtest, suggesting possible caudate involveme nt with clock drawings in dementia in general and of the Alzheimer`s type i n particular. Copyright (C) 2000 John Wiley & Sons, Ltd.